Writing stylus



FIG. 1 is a perspective view of a writing stylus showing our new design;

FIG. 2 is a right side elevation view thereof, which is a mirror image of a left side elevation view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a bottom plan view thereof;

FIG. 5 is a front elevation view thereof; and,

FIG. 6 is a rear elevation view thereof.

The broken lines in the following drawings form no part of the claimed design. 

The ornamental design for a writing stylus, as shown and described. 